In recent years, Owing to the emergence of the advanced information age, information transmission has been in trends of high speed and high frequency, and microwave communication and millimeter-wave communication have been in reality. For circuit boards in such high frequency age, materials with low dielectric tangents are required in order for transmission losses at high frequency to be minimally reduced, and cycloolefin polymer attracts attention as such material.
For example, Patent Document 1 discloses a technique for obtaining a multilayer board through: applying polymerizable composition which contains norbornene based monomer, metathesis ring-opening polymerization catalyst and peroxide such as di-t-butylperoxide onto a rough surface of an electrolytic copper foil; covering the surface with a glass-fiber reinforced PTFE resin film; making the copper foil side adhere to an aluminum plate heated to 145° C. for one minute and polymerizing the above composition; thereafter peeling away the glass-fiber reinforced PTFE resin film thereby obtaining a copper foil with resin; then clipping a both-sided copper-clad laminate board of CZ-treated glass epoxy with the copper foils with resin such that the resin sides are located inside thereof; and heat pressing them during 15 minutes at 200° C. under the press pressure of 5.2 MPa.
In addition, Patent Document 2 discloses that a laminated board was obtained through: coating mixture liquid obtained by mixing 2-norbornene, metathesis polymerization catalyst, 1,3-di(2-t-butylperoxyisopropyl) benzene (one-minute half-life temperature being 175° C.), etc. onto a supporting film of continuous polyethylene naphthalate film, heating them in a heating furnace at 150° C. during 30 seconds thereby polymerizing, rewinding the obtained film on the support film by using a film rewinding section with the support film; thereafter clipping a both-sided copper-clad laminate board of CZ-treated glass epoxy with the above film; and heat pressing them during 15 minutes at 200° C. under the press pressure of 5.2 MPa.
Patent Document 3 discloses that a laminated board was obtained through: impregnating polymerizable composition which contains norbornene based monomer, metathesis ring-opening polymerization catalyst and peroxide such as di-t-butylperoxide into glass cloths and then polymerizing thereby produsing prepregs; next laminating three layers of obtained prepregs and clipping them from both sides with copper foils; and heat pressing them thereby hardening. However, it is desired to further reduce dielectric tangents at high frequency bands in such laminates disclosed in these documents.
[Patent Document 1] International Publication No. WO2004/003052
[Patent Document 2] International Publication No. WO2004/069895
[Patent Document 3] International Publication No. WO2004/003052